流固耦合作用下水平定向孔壁稳定性分析  

Stability Analysis of a Borehole Wall during Horizontal Directional Drilling in Fluid-Solid Coupling Condition

作　　者：王建强[1,2] 李国民[1,2] 赵洪波[1,2] 简崇林[1] 

机构地区：[1]中国地质大学(北京),北京100083 [2]中国地质大学(北京)国土资源部深部地质钻探技术重点实验室,北京100083

出　　处：《地下空间与工程学报》2012年第4期796-801,共6页Chinese Journal of Underground Space and Engineering

摘　　要：孔壁失稳是目前水平定向钻进工程中经常遇到的一个实际问题,尤其是在地表的第四纪松散地层中钻进孔壁失稳更是屡见不鲜,严重影响工程施工。针对以往研究中没有考虑渗流场对孔壁稳定性的影响问题,本文在Biot固结理论的基础之上,建立了应力场和渗流场耦合数学模型,采用有限元方法对所建立的模型进行求解。通过对某一水平定向钻进孔壁稳定性进行数值模拟,分析了在流固耦合作用下地层孔隙压力、有效应力和位移的变化规律,并分析了在不同的冲洗液压力下,地层沉降情况。研究发现,在定向钻进过程中,流固耦合作用对地层特别是井壁附近围岩的应力和变形影响很大。研究结果为钻进过程中避免孔壁失稳,合理选择冲洗液及冲洗液压力提供理论依据。Borehole instability is often encountered in horizontal directional drilling projects that is a practical problem, especially in the loose surface of the Quaternary strata, the borehole instability is common, and has serious impact on the construction work. Due to the fact that the influence of the seepage field on the borehole stability prob- lem was not considered in previous studies, this paper on the basis of the Biot consolidation theory, develops a cou- pling mathematical model for the stress field and the seepage field, and using the finite element method to solve the model. In addition, through numerical simulation for the borehole stability of a directional drilling hole, the paper an- alyzes the effect of the fluid-solid coupling on pore pressure, effective stress and displacement of the soil around the borehole, and also analyzes the ground settlement under different fluid pressures. Simulation results show that the flu- id-solid coupling in horizontal directional drilling has great influence on stress field and deformation field of borehole soil. The results can provide a theoretical basis for the drilling process to avoid the instability of the borehole and how to select a reasonable mud and mud pressure.

关 键 词：流固耦合 孔壁稳定 有限元 数值模拟 

分 类 号：P634.8[天文地球—地质矿产勘探]